Register regulator for printing presses



Feb. 2l, 1950 l..` c. PooLE A 2,497,909

REGISTER REGULATOR FOR PRINTING PRESSES Filed nec. 1o, 194e 5 sheets-sheet 1 INVENTOR /oyo/C. Poo/e.

M W l Feb. 2l, 1950 C, PQOLE REGISTER REGULATOR RoR PRINTING PRESSES Filed Dec. 1o. 1944s.-

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A ORNE Feb. 21, 195o L. c. PQQLE 2,497,909

REGISTER REGULATOR FOR PRINTING PRESSES Filed Dec. 10, 1946 5 Sheets-Sheet 5 4 759? I l 5o 65 ea 52 e4- 45 wlTNEssEs:

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" A RNEY Feb. 21, 1950 Filed Dec. l0, 1946 L. C. FOOLE- REGISTER REGULATOR FOR PRINTING PRESSES 5 Sheets-Sheet 4 INVENTOR ATT RNEY Feb. 2l, 1950 C, PQOLE 2,497,909

REGISTER REGULATOR FOR PRNTING PRESSES Filed Dec.. l0, 1946 5 SheeS-Sheeb 5 WITNEssEs; 296 if INVENTOR 54W .Noya/c. P001?. i l l5 BY "'U Z 29e l UNITED STATES PATENT OFFICE REGISTER REGULATOR FOR PRINTING PRESSES Lloyd C. Poole, Lakewood, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 10, 1946, Serial No. 715,239

13 Claims. (Cl. lOl- 181) l My invention relates to register regulators for multi-color printing presses and, more particularly, to regulators for controlling the longitudinal register of multi-color rotary presses.

2 mentioned component colors. Usually, another color (monotone) is printed on the side of the web opposite to that receiving the color print and, as a rule, is not registered with the color print.

It is an object of the invention to provide a 5 Such a monotone printing stand is also provided register control capable of securing an accurate in the printing press according to Fig. 1 and register between the differently colored prints precedes the color presses proper as regards the with the aid of photo-electrically controlled detravel of the web. vices that require a lesser number of photo- According to Figure 1, the paper web I is taken electric scanning means and associated electronic from a supply reel 2 and passes over guide rollers, circuits than heretofore necessary in such consuch as those denoted by 3, into the monotone trol systems, printing stand, where it is held in contact with Another object of my invention is to provide the monotone printing roll PM by the appertaina register control of the kind mentioned which ing counter-roll 4. Thence, the Paper passes is distinguished by a very rapid response of the over a steam-heated drier DM. register control motors to the occurrence of mis- From the drier of the monotone printing zstand, register thus affording a correspondingly great the web travels in the direction of the arrow Al accuracy of register. and in contact with guide rollers into the yellow Still another object is to devise a multi-color printing stand, where it is held in contact with register control system capable of visually indi- 2o the yellow printing roll PY by the appertaining eating any occurrence oi' misregister as well as counter roll 5. The yellow printing roll PY prints the direction of such misregister relative to the equally spaced register marks, for instance dots, printing cylinder. alongside the yellow imprint. As the paper These and other objects of the invention, as leaves the roll PY, it passes over a roller 8 in well as the means provided by the invention for proximity to a photo-electric scanner SY whose achieving them will be apparent from the emoptical system is focused on the series of register bodiment exemplified in the drawings and demarks so that a series of corresponding electric scribed hereinafter. impulses is issued by the scanner. From the In the drawings; Y scanner, the web passes over a heated drying Figure 1 is a schematic illustration of a four- 30 cylinder DY and thence over guide rollers into the color printing press equipped with a register conred printing stand. trol in accordance with the invention; Thus traveling, the web passes over a compen- Fig. 2 represents a wiring diagram for the sating roller 1 which is journalled in a carrier 8. register control of Fig. 1; This carrier has a threaded portion in engage- Fig. 3 (upper portion) shows, in detail, an em- 35 ment with a revolvable nut 9 which has an extebodiment of one of the photo-electric scanners rior gearing in engagement with a worm l0 on the appertaining to the register control according to shaft of a register control motor MR. This Figs. 1 and 2; the same ilgure (lower portion) motor is reversible and is controlled by a motor shows alsol the circuit diagram of a power supply control unit CR to shift the compensating roller unit for the scanner; 40 l horizontally in one or the other direction in Fig. 4 represents an embodiment of one of the order to shorten or lengthen the loop of web mixer units appertaining to the register control material between the yellow and red printing according to Figs. 1 and 2; and stands, for the purpose of maintaining the red Fig 5 is an embodiment of a motor control imprint in register with the yellow imprint. The system for one of the register control motors also motor control unit CR is controlled by an elecappertaining to the register control of Figs. 1 tronic mixer unit denoted byYRwhich is conand 2, f nected to the scanner SY of the yellow printing The register regulator represented by the drawstand and also to a scanner SR in the red printings is designedl to automatically control the ing stand. The motor control unit CR is also longitudinal register of the four imprints sucequipped with a manually actuable control (push cessively produced in a multi-color press operating on the four-color combination principle of yellow, red, blue and black. The four-color prints are produced in four corresponding printing stands arranged in the sequence of the just u button station) BR which has a push button I2 for causing the motor to move the red imprint ahead and another push button I3 for moving the imprint back. The red printing stand is further provided with an indicating device IR which is electrically connected with the mixer YR and exhibits a visual indicationof any misregister and distinguishes between the forward or backward direction of such misregister. From thev compensating roller 1, the web passes over a manually adjustable roller I4 to a roller I5 appertaining to a photo-electric scanner SR which has its optical system focused onto the series of register marks printed on the web by the yellow printing roll PY. The web then passes along the red printing roll PR and is held in proper engagement therewith by the counter roll I6. After leaving the printing roll PR, the web passes over a drier DR toward the blue printing stand.

Along its further travel, the Jweb engages a compensating roller I1 which is adjustable by a reversible motor MB under control by a control unit CB substantially in the same manner as the compensating roll 1 above referred to. The motor control system CB is. in turn, controlled by a mixer YB in response to the occurrence of misregister detected by the yellow scanner SY in conjunction with a scanner SB in the blue printing stand. The mixer YB is electrically connected with an indicating device IB for visually f exhibiting the occurrence and direction of mis- I register.

'ped with a push button station BB whose push The motor control system CB is equipbuttons I9 and 20 permit a manual adjustment of the web compensating roller I1 to shift the blue impression (to be printed) in the forward and reverse direction relative to the yellow imprint. A manually adjustable roller 2l leads the web toward the photo-electric scanner SB and the appertaining roller 22 of the blue printing stand in which the printing roller PB and appertalning counter roller 23' produce the blue imprint. Thence, the web passes over the drier DB to the compensating roller 24 of the black printing stand.

Roller 24 is adjusted by a reversible motor MN under control by a motor control unit CN substantially in the manner described previously with reference to roller 1. The control unit CN is governed by an electronic mixer YN which compares the impulses from the yellow scanner SY with those of a scanner SN in the black printing stand, in order to cause the motor to adjust the roller 24- for eliminating any misregister of the black imprint. A push button station BN with push buttons 26 and 21 permits the operator to shift the black imprint ahead or back relative to the web. Operated from the mixer YN is a register indicator IN. From the compensating roller 24,

the web passes over a manually adjustable roller 28 along the scanner SN and the appertaining roller 29, and thence between the black printing press PN and the appertaining counter roller 30. After being dried in engagement with a heated drying cylinder DN, the web leaves the black printing stand in the direction of the arrow A2 to enter the folding equipment (not shown) of the machinery.

The printing rolls PM. PY, PR, PB and PN are suitably geared together and operated by a common drive motor (not illustrated).

The motor control units CR, CB and CN are electrically connected with a master control system CM which has a push button station BM equipped with a start button 32 and a stop button 33, in order to permit energizing and deenergizlng the register regulator, respectively. The station BM has further a push button 34 which, when actuated, sets the register control for manual operation by the above-mentioned stations BR.,

BB and-BN, while a push button 35 is provided for adjusting, when actuated. the register regulator for automatic performance.-

The register marks of the yellow printing roll PY are equally spaced around the periphery of this roll so that a given number, for instance sixteen marks, are printed on the web for each revolution of the roll in a fixed position with respect to the yellow imprint on the margin of the web. By properly austing the compensating rolls 1, I1 and 24, and the manually adjustable rolls I4, 2I and 28, the length of the web between the printing stands can be varied to obtain an integral number of register marks along the web between each two successive scanners. The press is designed so that, with the automatic compensator rolls 1, I1 and 24 setto their mid-v positions, an integral number of impressions are obtained along the web between each two printing cylinders when the manually adjustable rolls I4, 2I and 28 are adjusted to obtain an integral number of register marks along the web between the respective scanners. When these conditions obtain, the printing cylinders are positioned to print the red, blue and blackv impressions in register with the yellow impression. Once the machine ls thus properly adjusted, the register control system functions automatically to maintain the impressions in proper register regardless of the occurrence of shrinking or other disturbances between the printing rolls. With the web moving and the printing cylinders in register, register mark images will simultaneously appear on, and disappear from, the cathodes of the photo-electric tubes located in the scanners. If this is the case,

` the impulses from the yellow scanner SY and, for

e out of register.

mstance, the red scanner SR, occur simultaneously in the mixer YR, so that no control stimulus is imparted to the motor control unit CR. As a result, the motor MR and the compensator roller 'I remain at rest. If the web shrinks, for instance, between the scanners SY and SR, or if the press cylinders expand and increase their mutual distance, the red and yellow impressions tend to come In this event, the electric impulses from the yellow scanner SY occur prior to `the impulses from the red scanner SR. This causes the mixer YR to apply the necessary con- Atrol voltages to the control unit CR which, in turn,

operates the compensating motor MR in the proper direction to increase the web length between scanners SY and SR. The compensating motor MR continues to run until the web length is corrected. Over-correction will cause the electrical impulses originating in the yellow scanner SY- to arrive at mixer YR later than the electrical impulses from the red scanner SR. As a result, the direction of the compensating motor MR will `be reversed. Consequently, the compensating motor armature will rapidly oscillate with small angular displacements when the red and yellow impressions 'are in register. The occurrence of misregster causes the motor armature to temporarily assume a different ever-decreasing angular position and the correct register is obtained when the angle is substantially zero.

The blue and black impressions are independently registered with the yellow impression in a manner similar to that employed to register the red impression with the yellow impression, except that the yellow scanner SY, the blue scanner SB, the mixer YB, and the motor control CB with motor MB are employed for blue registration. and that the scanner SY with vspective light sources of' these scanners.

scanner SN, mixer YN, control system CN, and motor MN are effective for black registration.

The photo-electric scanner should be equipped with optical systems that are, preferably, ad- .instable to insure sharpest photo-electric impulses i'or given register marks.

The wiring diagram shown in Fig. 2, for the register control according to Fig. l, is intended to represent mainly the cable and terminal connections of the various electric apparatus composing the control system. The bottom portion of Fig. 2, however, shows also details of the master control system CM with the appertaining push button station BM which will be referred to presently.

The master control systemI has the main power supply buses of the register control connected to terminals Li, L2 and L3 for attachment to an alternating current line. The master control system includes a main circuit breaker MBR whosecoii 40 controls the power supply to the system by means of three contacts 4I, 42 and 43. The contacts 4i and 43, when closed, apply energizatiori to a full-wave rectifier 44. A branched cable d5 is connected to the output terminals of this rectifier and leads to the scanners SY, SR, SB, and SN for energizing the re- Contacts 4I and 42 of the main breaker lMB control also the energization of a power transformer 45 whose secondary winding is connected to a branched power cable 4'! leading to the mixers and motor control systems of the regulator in order to supply alternating-current energization thereto. The start button 32 and the stop button 33 of the control device BM (Figs. 1, 2) control the circuit of the coil in the main circuit breal-rer MBR and are shown in Fig. 2 to form part of a two-position switch. The buttons 34 and 35 for manual and automatic operation, respectively, of the register regulator are shown to form parts of another two-position switch. The function of the latter switch will be referred to in a later place.

The scanners of the register regulator may all have a substantially identical design. Various designs of suitable photo-electric scanners are available. Consequently, the embodiment of such a scanner, shown in Fig. 3 and described below, should be taken merely as an illustrative example and, if desired, may be replaced by known scanners of different construction.

According to Fig. 3, the scanning apparatus has a light source 50 whose terminals 5I and 52 are connected to the cable in order to be energized by direct current from the rectifier 44 (see Fig. 2). The photo-electric tube 53 of the scanner and the light source are equipped with an optical system schematically shown at I4 (Fig. 3), so that the tube 53 is illuminated by light reflected by the travelingv paper web I. Hence, when Aa register mark appears at the focal spot of the optical system, the illumination of the tube cathode is changed and produces a corresponding change or impulse in the circuits associated with the tube 53. Attached to the tube circuit, is an electronic amplifier whose amplifier tubes are denoted by TI and T2. Attached to tube T2 is a coupling circuit of cathode-follower -type which includes a vacuum tube T3 whose stage gain is less than unity. The coupling circuit serves impedance matching purposes explained in a later place. The photo-tube 53 and the circuits of tubes TI, T2. kT3 are energized from direct-current mains 55 6 and It whose terminals 51 and 58 are connected by respective leads 59 and G0 to the output terminals 6I and 62 of the appertaining power supply unit PSY (Figs. 2, 3), to be energized by direct current of constant voltage. The output voltage of the scanner SY in Fig. 3 appears across the terminals 51 and 63. The latter terminals are connected by respective leads 6I and 55 of a coaxial or shielded cable with the terminals |05 and ill'i of the mixer YR (Figs. 2, 3). Since the scanner SY shown in Fig. 3 represents the master or reference scanner" of the register regulator, the leads 64 and 65 are also connected to the mixers YB and YN (Fig. 2). The scanner SR of the red printing stand has its terminals. corresponding to terminals 5l' and 63 of scanner SY, connected only to the mixer Yl., the scanner SB of the blue printing stand has the corresponding terminals connected to the mixer YB, and the scanner SN oi the black printing stand has these terminals connected to the mixer YN. In other respects the design and function of the color scanners SR, SB, SN may be similar to that of the reference scanner SY shown in Fig. 3.

It will thus be recognized that the photo electric impulses from tube 53 in the reference scanner SY, upon amplification and modification in the circuits of the associated tubes Ti, T2 and T3, are impressed on the mixer YR and are compared by this mixer with the amplified impulses issuing from the output terminals of the red scanner SR. Similarly, the impulses from the reference scanner SY are compared in mixers YB and YN with the impulses coming from color scanners SB and SN, respectively.

A more detailed description of the scanner SY in Fig. 3 will now be given. The direct-current voltage between the energizing mains 55 and 56 is applied to the photo-tube 53 through a resistor 61 and a capacitor 58 which serve for smoothing and filtering. The photo-tube circuit includes a load resistor 69. The voltage drop appearing across resistor 69, and the photo-electrically controlled changes of this voltage drop, are applied to the grid circuit of the first amplifier tube TI. This grid circuit includes a capacitor l0, a grid resistor Il for obtaining the proper bias o-n the control grid of tube TI, and a capacitor l2. Resistor 'I3 serves Calibrating purposes. The screen grid connections of tube Ti include a voltage dropping resistor 14 and alternating-current bypass capacitors l5. Bypass capacitors 16 for a1- ternating current are provided in connection with the plate load resistors 11 and 18 of tube Ti. The amplied output voltage across the resistor 'il is applied to the tube T2 whose circuits are similar to the above-described circuit of tube TI, except that the-plate circuit of tube T2 includes a reactor and a resistor 8| for improving the high-frequency response. The proper grid bias for the tube T3 is obtained from a potentiometric resistance arrangement 32, and the output from tube T3 is impressed across the above-mentioned output terminals 51 and 63 of the scanner.

With photo-tube 53 illuminated, the voltage impressed across capacitor 58 is at a. maximum and equal to the voltage drop across resistor 6l. The current flow through resistor 69 is zero, and the voltage applied across the grid circuit of the amplifier tube TI is negative and equal to the normal self grid bias voltage. A reduction oi illumination on photo-tube 53, produced by a register mark entering the focused light beam, will cause capacitor 68 to partially discharge. The discharging current,'which flows through resistor t9, increases the negative voltage at the control grid or tube TI. During this transient state, the plate current of tube TI is momentarily decreased. but returns it to normal after the register mark has passed through the light beam. As the plate current of tube Tl ows through the plate load resistor 11, the grid voltage on the control grid of tube T2 assumes a less negative value, so that the plate current of tube T2 is momentarily increased. This increases the voltage across the load elements 89 and 8| of tube T2, so that the grid voltage of tube T3 momentarily assumes an increasingly negative value. Consequently, the cathode current of tube T3 is momentarily decreased. In summary, the scanner produces a sharp negative voltage impulse between the output terminals 51, 63 and the load potentiometer RY, mentioned hereinafter with reference to Fig. 4, connected across these terminals. In other words, the potential of terminal 63 in scanner SY (Fig. 3) becomes momentarily less positive with respect to the terminal 51 which is grounded. I

The power supply unit PSY shown in Fig. 3, which serves to impress constant direct-current voltage across the terminals 51 and 58 and the appertaining mains 55 and 56 of the scanner, is energized from the power transformer I6 through the cable l1 (Figs. 2, 3) and through an input transformer 83 whose secondary winding is connected to a full-wave rectifier tube Tl. The output terminals of tube T4 arev connected through a composite filter circuit 85 to two vacuum tubes T5 and T6 whose load consists of resistors 88, 89 and includes' an adjustable potentiometer 99. These load elements are series-connected across the output leads 9| and 92 which are attached to the above-mentioned output terminals 6| and 62 of the power unit. A regulatorV tube T1, in connection with a non-linear circuit element consisting of a neon tube T8, serves to regulate the output current for constant voltage. An arrangement of smoothing impedances 93 is also connected across the output leads 9| and 92.

A reduction of voltage across the leads 9| and 92 caused, for instance, by a fluctuation in the alternating-current line voltage applied to the rectier tube T4, increases the negative grid voltage in the vacuum tubeTI, thus causing less current to flow through the bias resistor' 95. As a result, the voltage drop across resistor 95 is also decreased and reduces the magnitude of the negative voltage applied to the grids of the vacuum tubes T5 and T6. This, in turn, decreases the voltage drop across the leads 9| and 96 and immediately restores the voltage across the leads 9| and 92. Conversely, an increase of voltage across leads 9| and 92 increases the voltage drop across leads 9| and 96 with the result of immediately restoring the voltage across the output leads 9| and 92. The magnitude of the output voltage across leads 9| and 92 may be changed or calibrated by adjusting the potentiometer 99.

The power unit PSY, shown in Fig. 3 and described in the foregoing, is similar to the power unit Ps (Figs. 1. 2) for the scanners sa, SB and i SN. As will be seen from the following description of the mixing units, these units are likewise equpped with a power supply section of a design similar to the one just described in conjunction with Fig. 3.

The mixer unit YR, shown in Fig. 4, comprises adirect-current power supply unit, two Sharpener and associated detector circuits, two amplifiers, and a direct-current switching and delay circuit. The appertaining register indicator IR for the red printing stand is electrically associated with the amplier stage of the mixing panel and also shown in Fig. .4.

The direct-current power unit of the mixer comprises the full-wave rectifier tube T9. two control tubes Tl 9 and Tl l, regulator tube Tl2 and a neon tube TIS. The rectifier tube T9 is energized fromthe terminals |9| and |92 through a transformer |93. Terminals |9| and |92 are connected to the branched power supply cable 41 (see also Fig. 2). The rectifier and regulated output voltage of the power unit is impressed across the output leads |95 (positive) and |95 (negative). The power unit, comprising the tubes T9, Tl, Tl T|2 and Tl3, is of a design and functioning similar to the power unit PSY and the respective tubes T4, T5, T9, T1 and T9, as illustrated in Fig.

3 and described in the foregoing. Hence, a de' tailed description and further explanation of the power unit of' the mixer shown in Fig. 4 is unnecessary.

The sharpener and detector circuits of the mixer according to Fig. 4 comprise tubes TM, TIB.

and TIS, Tl'l, respectively. These tubes are plate-energized from the output leads |94 and |95 of the power supply unit. The grid controll for the Sharpener tube TH is derived from the above mentioned potentiometer rheostat RY whose terminals |95 and |97v are connected to the output leads 64 and 65, respectively, of the master scanner SY shown in Fig. 3 (see alsorFig. 2). Therefore, the potentiometer RY shown in Fig. 4 represents the plate load for the amplifier tube T3 of the master scanner SY shown in Fig. 3.

Similarly, the grid control for the Sharpener tube TIS according to Fig. 4 is derived from a pottntiometer rheostat RR whose terminals |99 and |99 are connected in the plate circuit of the last amplifier stage in the red scanner SR (seel Fig. 2).

Reverting to Fig. 3, the function of the pentode T3 will now be more fully explained. The master scanner and color scanners, located at the respective printing stands, are relatively remote from the mixer units, the latter being preferably arranged in a centrally located control assembly. As mentioned, the connection between the scanner and mixer is established by shielded transmission cables such as are available with concentric or twisted conductors. rThe impedance of cables of this sort is relatively low, for instance, in the order of 100 ohms. The impedance of vthe scanners, without the coupling circuit, of which the tub-e T3 (Fig. 3) forms part, is of a higher order, for instance several hundred thousand ohms. However, with tube T3 and the resistor 82 series-connected across terminals 63 and 51, the output impedance between these terminals is in the order of 100 ohms and, hence, matches the input impedance of the cable (64, 65) when the cable is properly terminated at the receiving end. The resistance of the potentiometer rheostat RY (Fig. 4) at the receiving end, across terminals |99 and |91 approximates the impedance of the transmission cable. As a result of these impedance matching means at both cable ends, a faithful transmission of the scanner impulse wave shape to the mixer is achieved at the expense of the de-ampliication occurring in the circuit of tube T3. The transmission between the color scanners and the respective mixers is designed and operative in asimilar way thus contributing to the desired high accuracy of register control performance.

79 The two amplifier tubes Titi and Tl@ in the amplifier stage of the mixer are grid-controlled by voltages derived from the respective plate cirplate current in the tubes TIB and TIS to inf l dicate a misregister in one or the other direction.

The switching and delay circuit of the mixer includes two tubes T and-TM. These tubes are grid-controlled by the respective tubes THB andTI and receive plate energizat/ion from a direct-current source which is located in the motor control unit CR and will be later described with reference to Fig. 5. The terminals denoted in Fig. 4 by ||3, II4, II5 and IIS, respectively, are connected with respective terminals ||1, IIS, IIB and |20 shown in Fig. 5 (see also Fig. 2).

The design and operation of the mixer YR according to Fig. 4 will now be described more in detail.

The rst Sharpener circuit of the mixer YR is composed of tube TI4, resistors |25, |26, |21, |28, |29, and capacitors |3I, |32, |33.

The second Sharpener circuit includes the tube TIB, resistors |35, |36, |31, |28, |29, |30, |38 and capacitors |4I, |42, |33.

These two sharpener circuits are closely associated with the respective detector tubes TI5 and TI1. Plate voltage, obtained from the leads |04 and |05 of the direct-current power unit of' the mixer, is applied to the detector tubes T|5 and TI1 by means of the positive lead |45, the resistors denoted by |46 through I5|, and the negative cathode lead |52. Resistors |46, |41 and |48 represent the plate load of tube TI5. Resistors |49, |50 and |5| represent the plate load for tube TI1. A plate and screen current bypass capacitor for both tubes is denoted by |54, while numerals and I 56 denote bypass capacitors for the plate load resistors of TI5 and TI1, respectively.v Numerals |51 and |58 indicate filter capacitors.

Negative voltage is applied to the suppressor grids of tubes T|5 and TI1 by means of the negative lead |05 and the resistors |59 and |60. Nullifying voltage of positive polarity is applied to the suppressor grid of tube TI 5 through a resistor |6| connected to the plate of tube TI1. Nullifying voltage of positive polarity is supplied to the suppressor grid of tube TI1 through a resistor |62 connected to the plate of tube T|5. Interelectrode capacitance (suppressor-plate) of tube TI 5 is neutralized by a capacitor |63, and interelectrode capacitance (suppressor-plate) of tube TI1 is neutralized by a capacitor |64. Screen voltage for tubes T|5 and TI1 is supplied from a voltage dividing resistor |65 connected across the output leads |04 and |05 of the power supply unit Tubes T|4 and T|6 and their associated circuits are used to sharpen the impulses received from the scanners. The modified impulses are applied to the control grids of tubes TI5 and TI1, respectively.

Capacitor |32 is charged through resistors |25 and |30. The voltage applied to the charging circuit is obtained from lead |04 and lead |52. The time constant of the circuit has been chosen to allow capacitor 32 to charge during the elapsed time between the impulses received from stanner SY.

'I'he control grid of TI4 is connected to ground through current-limiting resistor |26 and lead The cathode of Tiri is connected to lead i1@ through cathode resistor |21 so that resistors |20 and |23 form a voltage divider circuit across leads |52 and i'i. A bias voltage ior tube THE is thus obtained across resistor I 28 which is sufcient to prevent the tube from conducting, provided there is no current flowing in cathode resistor I2?.

Capacitor i 3|, connected between the tap of rheostat RY and the cathode of tube TI4, is charged, during the time elapsing between the impulses received from scanner SY, by an applied voltage which isequal to the difference of the voltages that occur on the one hand between leads |10|52 and on the other hand between the lead |52 and the tap of rheostat RY.

An impulse received from scanner SY will momentarily reduce the voltage across the lead |52 and the tap of rheostat RY, allowing the capacitor |3i to discharge through cathode resistor |21. The discharge current, which iiows through resistor |21, reduces the control grid voltage of tube T|4 to a value less than the critical characteristic value of tube T|4 (the charging current of capacitor |3| increases the control grid voltage which produces no disturbance within the tube), and capacitor |32 discharges.

The discharge current ows from capacitor |32 through tube TI 4, resistor |21, capacitor |33 and resistor |30, thus making point |14 negative with respect to lead |52. The discharge continues until the algebraic sum of the voltages around the discharge circuit is equal to the arc drop of tube TI4. At this point, the grid of tube TI4, which has again assumed a negative value with respect to the cathode, regains control and prevents the tube from conducting. Capacitor |32 then charges, thus completing one operating cycle.

Voltage is applied rapidly across resistor |30 when tube T|4 becomes conducting, which immediately charges capacitor |15 through resistor |16. As the charging current of capacitor |15 ows through resistor |16, a negative impulse (with respect to the cathode of tube T|5) of very short duration, is applied to the control grid of tube T|5. Positive impulses which are presented to the grid of tube TI 5 as capacitor |15 discharges are ineffective as tube T|5 operates at zero bias.

The other Sharpener circuit functions in the same manner as the Sharpener circuit just discussed, except the output impulse is applied to tube TI1.

The control grid bias of tubes T|5 and TI1 is zero. Plate voltages are supplied from lead |45 (positive) and lead |52 (negative). Negative suppressor grid voltages are supplied from lead |05 (negative) with respect to cathode lead |52. Taps |18 and |19 are positioned on resistor |65, so that for any position of potentiometer |80, the voltage applied to the suppressor grids of tubes T|5 and TI1 is negative with respect to the cathode lead |52. With zero control grid bias voltage on tubes T|5 and TI1, positive impulses do not influence the plate current of either tube T|5 or tube TI1. However, a negative impulse on the control grid oi' one tube will transfer the plate current of that tube to the other tube.

For example, a negative impulse on tube TI5 control grid will interrupt the ow of plate current and the anode of TI 5 becomes more positive, the suppressor grid of tube TI1 becomes less negative in relation to the cathode lead |52.

ll and tube T|1 will conduct more plate current. An increasev of plate current of tube T|1 causes its anode to assume a less positive voltage with respect to cathode lead |52 so that the suppressor grid of tube T|5 becomes more negative with respect to cathode lead |52, thus maintaining the tube in a non-conducting state.

Tube T|5 remains non-conducting until its negative suppressor voltage is removed by the interruption of the plate current in tubeTH due to the application of a negative impulse to its control grid. Such application oi a negative impulse to the grid will transfer the current iiowing' in the plate circuit of tube T|1 to the plate circuit of tube TIS.

If negative impulses are simultaneously impressed on the control grids of tubes T|5 and T|1, the tubes conduct alternately; plate current transfer occurring each time the impulses are received. This condition obtains in mixer YR, when the red impression is in register with the yellow impression. The action may be more clearly understood by noting that the time constants of resistor-capacitor combinations |16, and |38, |39 are less than the time constants of resistor-capacitor combinations |46, |55 and |49, |56.

For example, assume tube T|1 to be conduct-- ing. Under this condition, capacitor |64 is charged to a higher voltage than is capacitor |53.

When the simultaneous impulses arrive at the control grids, the suppressor grid of tube T|1 will assume a greater ,negative potential with respect to lead |52 than will the suppressor grid of tube TI 5. Obviously, when the simultaneous impulses on the control grids subside, tube T|5 will conduct and tube T|1 will not conduct.

Tube TIB amplies the voltage drop appearing across a portion of the plate load resistors of tube T|5 i. e., the voltage across resistors |46 and |41. Likewise, tube T|9 ampliiles the voltage across a portion of the plate load resistors of tube Tl1, namely, resistors |49 and |58.

Plate, screen and grid bias voltages are supplied for tubes TI8 and Tl 9 by a voltage doubling and rectiier arrangement consisting of a transformer lill, set of rectiilers |85, capacitors |86,4

|81, a resistor |88 and a potentiometer rheostat |89. The grid bias voltage, which is separately iltered by capacitor |90, may be adjusted by means ofthe potentiometer rheostat |89. The screen grids of tubes Tl8, T19 are bypassed by a capacitor IJI. A bypass capacitor |92 is provided for the plate load resistors |93 to |96. Numerals |91 and |98 denote current-limiting resistors for the ray control elements of externally connected tube T22 in the register indicator IR. Resistors |99 and 200 forma voltage divider which applies voltage to the target oi the indicator tube T22. l

With tube T|5 conducting current and tube T|1 not conducting current, tube T|8 will receive suicient negative bias voltage to be prevented from conducting. Tube T|9 receives a minimum amount of negative grid voltage, determined by potentiometer |89, and sufllcient current will flow in lead and through resistor |95 to bias tube T2| to cut-o. However, as tube TIO is not conducting, the voltage drop across resistor |94 is a minimum. This minimum value of voltage, which is applied to the control grid of tube T20, is sufficiently low to allow tube T20 to conduct. For similar reasons, tube 20 isnon-conductive when the conditions are such as to render tube T2| conductive.

4) are connected to the respective "terminals H1, .l

H8, H9, |20 0f the mixing unit (Fig. 5), it Will be seen that the tubes T29 and T2| (Fig. 4) operate as direct-current switches to energize and deenergize the direct-current windings 2|2, -2I3 of saturable reactors Rl and R2, respectively (Fig. 5). When the bias of tube T29 is removed, current ows from the positive lead 2| of the directcurrent power source located in the motor control unit (Fig. 5) through the then closed contact 2 I5, the direct-current coil 2I2 of reactor R|, resistor 2|6, terminal ||1, terminal ||3 (Fig. 4), tube T28, cathode lead 2|8, terminal H6, terminal |20 (Fig. 5) andlead 220 back to the negative side of the direct-current power supply of the motor control unit CR. When the bias of tube T2| is removed, current ows through the direct-current coil 2|3 of the reactor R2 (Fig. 5).

For large values of misregister, the voltage across leads 22| and 222 (Fig. 4) will remain constant. are approached, the impulses received across rheostats RY and RR from the scanners SY and SR. respectively, arrive practically simultaneously. The voltage across leads 22| and 222, therefore, reverses its polarity each time a register mark enters the optical system of the yellow scanner SY. Owing to the time constants of the circuits in which the direct-current coils of reactors R| and .R2 are located, these reactors cannot be saturated and desaturated at frequencies above a Afrequency corresponding to about three-fourths of the speed of the press. A' delay circuit, consisting of capacitor 223 and a potentiometer 226i, is thereforeinserted across leads 22 222 and may be ad- Justed to obtain best overall results.

Target'voltage for the Yregister indicator tube T22 is obtained through the voltage divider resistors |99 and 28o connected across the direct-f current source. One ray control electrode is connected through resistor i9? to the anode of 'tube Til. The other ray control electrode is connected through resistor |98 to the anode of tube T|9.

Provided the register regulator has been synchronized with the press, the register indicator indicates the position of the yellow impression-as it passes through the roll stand on which the indicator is located. Should the web shift oi register, theregister indicator will indicate the direction of misregister.

If the web is in advance oi the in-register position (0E-register on the left side), the impulses from the yellow snner will be the last to arrive. Tube T| 5 and tube Ti@ do not conduct current while tubes TIT and Tit conduct. The ray control voltage for the ray control circuit attached to tube Tl@ will be a minimum. The other ray control voltage will be a maximum.

Under these conditions, a shadow will be cast on the left side of the register indicator tube T22 indicating that the web is ofi-register to the left side. Similarly, if the web is oil-register to the right, a shadow will be cast on the right side or the register indicator tube.

When the web is in-register, light will be cast over each shadow area of the indicator tube each time a register mark passes the yellow scanner. Due to persistance of vision, the two shadow areas v of the register tube will then appear to be equally However, as perfect register conditions in Fig. 5, serves to govern the regulating perfomance of the reversible motor MR for the red printing stand. This motor is also shown in Fig. 5, its armature is denoted by 228, its field winding by 229 and an appertaining field rheostat by 236. Fig. shows also the push button station BR appertaining to the motor control unit CR of the red printing stand.

According to Fig. 5, the motor control unit CR includes three electromagnetic relays ICR, ZCR and 3CR. These relays are controlled by the master push button station BM (Fig. l) and, more particularly, by the appertaining switch containing the push buttons 34 and 35 (Fig. 2), and these relays are also under control by the push buttons I2 and i3 of the push button station BR (Fig. 5) of the red printing stand. This will be set forth more in detail in a later place.

The motor control unit CR according to Fig. 5 is provided with two full-wave rectifier tubes T23 and T28 of which the tube T23 provides exciting voltage for the motor field winding 29. The unit CR includes also two pairs of thyratron tubes denoted by T24, T25, and T26, T21, respectively.

The rectifier tube T28 forms part of the directcurrent power supply source for the direct-current control coils 2 i2 and 2|3 of the saturable reactors Ri and R2, these coils being controlled by the switching tubes T and T2i, respectively, of the mixer panel (Fig, 4). The anodes of tube T28 (Fig. 5) are connected to the mid-tapped secondary winding 23| of a transformer 232 whose primary is energized from the power terminals 233 and 234 of the control unit. Terminals 233 and 234 are connected to one branch of the power supply cable 41 (see Fig. 2) and hence receive energization when the main circuit breaker MB is closed. The current rectiiied by tube T28 (Fig. 5) is filtered by a reactor 235, a capacitor 236 and a resistor 221.

The reactors RI and R2 have respective alternating-current coils 231 and 238 whose reactance is high when the appertaining magnetic reactor core is unsaturated. but drops to a low value when the core is saturated by the excitation of the appertaining control coil 2I2 or 2|3. The alternating-current winding 231 of reactor RI is connected to another secondary 239 of transformer 232. The alternating-current coil of reactor R2 is connected to a transformer 240 which 'receives primary energization from the power supply terminals 233 and 234. The connection of winding 239 with coil 231 includes a resistor 24| and a capacitor 242; and a similar resistor 253 and capacitor 254 are connected with the circuit of coil 238 oi reactor R2.

Coil 231-of reactor RI, resistor 24| and capacitor 242 are elements of a phase shift circuit whose output voltage is applied to a transformer 255 The reactor winding 238 with resistor 253 and capacitor 254 forms another phase shift circuit which is output-connected to a transformer 215.

Connected across'the power terminals 233 and 234 of the motor control unit CR (Fig. 5), is also the primary winding 243 of a transformer 244 which has five secondary windings denoted by 245 through 249.

The grid voltages of tubes T26 and T21 have an alternating-current component and a directcurrent component. component of the grid voltage for, tube T26 is displaced 180 electrical degrees with respect to the alternating component of the grid voltage for tube T21 and is supplied from the secondary winding of transformer 255 through a current- The alternating-current limiting resistor 25. The alternating-current component ci the grid voltage iol tube T21 is supplied from the same transformer 255 through a current-limiting resistor 525i.

The direct-current bias voltage applied to the grids of tubes T25 and T21 is obtained from two sources operative in series with each other. One of these sources comprises a full-wave rectifier 252 energized vfrom the secondary winding 24S of the transformer 2135. A capacitor 256 and a resistor 259 are connected in parallel to each other across the output terminals of the rectifier 252. The other source of direct-current grid bias comprises the secondary winding of transformer 255, the current-limiting resistors 255 and 251, a resistor 26B, a capacitor 26|, and the tubes T26 and T21. Both sources deliver an adequately ltered, full-wave reotled current. Similar capacitors, resistors and appertaining elements are employed in connection with the thyratron tubes T24 and T25.

As stated above, reactors Ri and R2 (Fig. 6) are controlled by tubes T22 and T2| (Fig. 5), respectively. With no current flowing in tube T2|, saturable reactor R2 is desaturated. Consequently. a phase shifted alternating-current grid voltage is applied to the control grid and cathode of thyratron tube T21. A similar control grid voltage, except displaced 180 electrical degrees, is applied to the control grid and cathode of thyratron tube T26.

The direct-current grid bias voltage which is applied to the control grids of thyratron tubes T26 and T21 is the sum of the voltage drops across resistors 259 and 260. The voltage across resistor 259 is obtained from rectifier 252. The voltage across resistor 260 is obtained from the full-wave rectifier circuit consisting of transformer 255, grid and cathode elements of tubes T26 and T21 and capacitor 26|.

The direct-current grid bias voltage is approximately equal to the maximum value of the alterhating-current component of the grid voltage applied to tube T26 from transformer 255, minus the grid to cathode arc drop in thyratron tube T26. Consequently, the voltage across the filter, comprised of capacitor 26| and resistor 260, will change with any changes in line voltage and the direct-current grid bias voltage will remain at a constant value.

When reactor RI is desaturated, the alternating-current component of the grid voltage of thyratron tube T21 leads the anode voltage by 60 electrical degrees, allowing the instantaneous grid voltage to exceed the critical grid characteristic at the start of the cycle. Tube T21 then conducts current every half-cycle. Similar condit-ions obtain for thyratron tube T26 during the following half-cycle.

When reactor RI is saturated, the alternatingcurrent grid voltages applied to thyratron tubes T26 and T21 lead the corresponding anode voltages of the tubes by electrical degrees. With positive anode voltage on either tube, the instantaneous value of the grid voltage exceeds the critical grid characteristic and the tubes cannot conduct.

Reactor R2. transformer 215 and associated resistors 216, 211, 219, 280, 200, capacitors 21|, 218, and rectifier 25| control the thyratron tubes T24 and T25 in a manner similar to that of the corresponding circuit elements described above for thyratron tubes T26 and T21.

From the above description, it will be recognized that the motor armature is operated in ateneo@ one direction by saturating the reactor R2 and desaturating the reactor RI. The armature current then flows from the cathodes of thyratron tubes T28 and T21 through lead 28|, resistor 282, lead 285, resistor 283, to the positive side of the armature 228, through the armature, lead 266, close contacts 284 of ICR, lead 285 and a contact of push button I2 to lead 288 of the transformer winding 248, where the current divides. One half of the'current flows through the transformer winding to the anode of tube T21 to cathode lead 28|. The remaining half of the current flows through the transformer winding to the anode of tube T26 to cathode lead 28|. Current will not flow from thyratron tubes T24 and T25 because reactor R2 issaturated.

By saturating reactor RI and desaturating reactor R2, the motor will operate in the opposite direction. Current then ows from tubes T24 and 'T25 through lead 29|, resistor 292, resistor 293 tov the positive side of the armature 228 (lead 265); thence through the armature, lead 285,

iid

5. When operating the push button i2 or i3 (Fig. 6), relay 2CR returns to normal open contact position and deenergizes reactors RI and R2. thus delaying the phase of the grid voltages of thyratron tubes T24, T25, T28, T21.

Operation of the push button I2 (Fig. 5) closes the anode circuits of tubes T24 and T25, and voltage is applied to the motor armature 228 Athrough lead 268 (positive) and lead 285 (negative). Operation of the push button i3 closes the anode circuits of tubes T28 and T21, and voltage is applied to the motor amature through lead 266 (positive) and lead 255 (negative).

While a description of the regulator performance as a whole has been given above, the iol- `lowing characteristics of the system will nowdbe closed contact 294 of relay |CR, lead 285, push button I3, lead 288, and back through supply transformer winding 241 and tubes T24 and T25.

It is assumed, in the foregoing description of the control performance, that the relays ICR, 2CR and 3CR of the motor control unit CR (Fig 5) are in energized, picked-up condition. That this is the case when the system is set for automatic operation, will be recognized from the following.

The control coil 300 of relay ICR is connected across the terminals 30| of the control unit CR.

Termin-als 30|, as illustrated in Fig. 2, vare connected by leads 302 and 303 with the corresponding relay terminals of the motor control units CB and CN and also the line terminals Li and L2 under control by the contacts 4i and 42 of the .main circuit breaker MB, and also under control ny the push button 35 of the switch appertaining to the master push button station. Hence, when the breaker MBR is closed by actuation of the start contact 32, and if the system is set for automatic performance by the actuation of the push button 35, the coil 300 of relay ICR. (Fig. 5) is energized and the relay contacts 284 and 284 complete the circuits of the leads 285 and 295, as described in the foregoing.

The control coil 304 of relay 2CR is connected across two terminals of the control unit CR of which one is denoted by 305. The other terminal is connected through a lead 308 and the push butf r-fntacts I2, I3 to a terminal 301 of the Push button station BR at the red printing stand. Terminal 301 of station BR, as shown in Fig. 2. is connected to the above-mentioned lead 302, and hence through the automatic push button contact 35 and the main breaker contact 42 to the line terminal L2. Terminal 305 (Fig. 5) of control unit CR is connected by a lead 308 (Eig. 2) to the corresponding terminals of the motor oontrol units CB and CN, and also with the line terminal LI through the main breaker Contact 4|. Hence, coil 304 of relay .2CR (Fig. 5) operaies in parallel connection to the coil 300 of relay ICR. and closes the contact 2|5 during the automatic performance. The coil 3|0 of relay 3CR is likewise connected in parallel to the coil 300 as is apparent from Fig. 5. Therefore, the relay 3CR opens its contacts 3|i and 3| 2 as is required for the above-described automatic regulating functions.

By operating the manual push button 34 (Fig.

2), the contacts of relays ICR and 3CR are re turned to their normal positions as shown in'Fig.'

readily apparent.

A regulator control according to the invention requires not more photo-electric scannerss and associated tube circuits than there are color presses. For instance, for the illustrated our color press, only one reference or master scanner at the rst (yellow) color press and only three color scanners 'at the red, blue, and black presses, respectively, are required. This distinguishes a regulator according to the invention favorably from known regulator systems in which one scannerwas located ahead of each color press and one immediately behind the press, thus requiring at least seven scanners for a four-color printing method.

The association of Sharpener circuits (including the tubes TM and Ti 5 in Fig. 4) with the detector circuits of the mixers permits operating with extremely short impulses from the photo-electric scanners. For instance, the illustrated system may operate with impulses from the scanners of not more than 10 microseconds duration. As a result, the system is further distinguished by an extremely high accuracy of performance.

In conjunction therewith, the automatic com-v pensation of line iluctuations eected, for instance. by the tubes TI2, Tia in Fig. 5, and tubes Td, T8 in Fig. 3, maintains the high accuracy of registering performance independent of disturbing voltage variations in the energizing alternating-current line.

Regulators according to the invention are fur ther advantageous in affording an easy and rapid manual adjustment of the press, for instance,

is set for manual operation, the relay SCR (Fig. 5)

is in the illustrated deenergized condition, and hence places the'resistors 282 and 252 into the armature circuit. This has the eiect of recalibrating the motor control unit for an increased motor speed during manual actuation. As a result, the regulator permits the elimination of 4excessive misregister within very short time.

It will be understood by those skilled in the art that the invention permits of various modications and alterations, especially as regards the individual apparatus units that compose the sysn tem, without departing from the objects and es sential features of the invention and within the v.scape of the claims4 defining the invention hereina'fter.

I claim as my invention:

l. A register regulator for registering imprints in multi-color printing, comprising a plurality of register control motors for registering respective subsequent imprints with the first imprint, a plurality of control units connected to said respective motors and having each a pair of control circuits for causing the appertaining motor to run in a direction depending upon which of said circuits is energized, an impulse-transmitting master scanner for issuing master impulses in* response to the passage of register marks of the first imprint, a plurality of impulse-transmitting reference scanners to be located ahead o the respective subsequent imprints for issuing reference impulses in response to the passage of said register marks, a, plurality of electronic mixer units each being connected to said master scanner and to one of said respective reference scanners to be controlled by said master impulses and said reference impulses and having two output circuits connected to said respective control circuits of one of said respective motor control units for energizing one or the other of said two circuits depending upon whether said master impulses lead or lag said reference impulses, whereby the motor appertaining to said one control unit is caused to run in the direction required to establish simultaneity of said impulses.

2. A register regulator'for registering imprints in multi-color printing, comprising an impulsetransmitting master scanner for issuing master impulses in response to the passage of register marks of the rst imprint, a plurality of impulsetransmitting reference scanners to be located ahead of the respective subsequent imprints for issuing reference impulses in response to the passage of said register marks, a plurality of electronic mixer units each being connected to said master scanner and to one of said respective reference scanners to be controlled by said master impulses and said reference impulses and having two output circuits, an electronic register indicator tube for visual indication having two deector electrodes connected to said respective output circuits so as to deect its indication either way depending upon whether said master impulses lead or lag said reference impulses, a plurality of register control motors for registering respective subsequent imprints with the ilrst imprint, and controllable reversing means for -said motor in order to make it run in the direction exhibited by said indicator tube for establishing simultaneity' of said impulses.

3. A register regulator for registering imprints in multi-color printing, comprising a plurality of register control motors for registering respective subsequent imprints with the first imprint, a. plurality of control units connected to said respective motors and having each a pair of control circuits for causing the appertaining motor to run in a direction depending upon which of said circuits is energized, an impulse-transmitting master scanner for issuing master impulses in response to the passage of register marks of the rst imprint, a plurality of impulse-transmitting reference scanners to be located ahead of the respective subsequent imprints for issuing reference impulses in response tothe passage of said register marks, a plurality of electronic mixer units each being connected to said master scanner and to one of said respective reference scanners to be controlled by said master impulses and said reference impulses and having two output circuits connected to said respective control circuits of one of said respective motor control units for energizing one or the other of said two circuits depending upon whether said master impulses lead or lag said reference impulses, so that the motor appertaining to said one control unit is caused to run in the direction required to establish simultaneity of said impulses, and an electronic indicator tube for visual indication having two defiector electrodes connected to said respective output circuits so as to deflect its indication to thereby exhibit the direction of any misregistry.

4. A register .regulator for registering imprints in multi-color printing, comprising a plurality of register control motors for registering respective subsequent imprints with the iirst imprint, a plurality of control units connected to said respective motors `and having each a pair of control circuits for causing the appertaining motor to run in a direction depending upon which of said circuits is energized, an impulse-transmitting master scanner for issuing master impulses in response to the passage of register marks of the rst imprint, a plurality of impuse-transmitting reference scanners to be located ahead of the respective subsequent imprints for issuing reference impulses in response to the passage of said register marks, a plurality of electronic mixer units each being connected to said master scanner and to one of said respective reference scanners to be controlled by said master impulses and said reference impulses and having two output circuits connected to said respective control circuits of one of said respective motor control units for energizing one or the other of said two circuits depending upon whether said master impulses lead or lag said reference impulses so that the motor appertaining to said one control unit is caused to run in the direction required to establish simultaneity of said impulses, a plurality of manually controllable means associated with said respective motors and having selective actuating means for permitting each motor to be individually operated in either direction under control by the operator, and selective master control means common to said motors and interlocked with said plurality of manually controllable ymeans so as to permit the operator to set the regulator for manual control of said motors and for automatic control by said control units respectively.

5. A register regulator for registering imprints in multi-color printing, comprising a plurality of register control motors for registering respective subsequent imprints with the first imprint, a plurality of control units connected to said respective motors and having each a pair of control circuits for causing the appertaining motor to run in a direction depending upon which of said circuits is energized, an impulsetransmitting master scanner for issuing master` impulses in response to the passage of register marks of the rst imprint, a plurality of impulse-transmitting reference scanners to be located ahead of the respective subsequent imprints for issuing reference impulses in response to the passage of said register marks, a plurality of electronic mixer units each being connected to said master scanner and to one of said respective reference scanners to be controlled by said master impulses and said reference impulses and having two output circuits connected to said respective control circuits of one of said respective motor control units for energizing one or the other of said two circuits depending upon whether said master impulses lead or lag said reference impulses so that the motor appertaining to said one control unit is caused to run in the direction required to establish simultaneity of said impulses, a plurality of manually controllable means associated with said respective motors and having selective actuating means for permitting each motor to be individually operated in either direction under control by the operator in accordance with the indication of said indicator tube, and selective master control means common to said motors and interlocked with said plurality of manually controllable means so as to permit the operator to set the regulator for manual control of said motors and for automatic control by said control units respectively.

6. A register regulator for registering imprints in multi-color printing, comprising a plurality of reversible register control motors for registering said imprints relative to one another, a plurality of control units connected Ito said respective motors and having each a pair of control circuits for causing the appertaining motor to run in a direction depending upon which of said circuits is energized, a plurality of impulse-transmitting photo-electric scanners for issuing control impulses in response to the passage of `printed register marks, a plurality of electronic mixer units each being input-connected to two of said scanners to be jointly controlled by the impulses from said two scanners and being output-connected to one of said control units respectively for energizing one or the other of said two circuits depending upon whether the impulses from one of said two scanners lead or lag those from said other scanner, an electronic indicator tube for visual indication having two 'deflector electrodes connected to said respective output circuits so as to deect its indication in accordance with the direction of misregister.

7. A register regulator for registering imprints in multi-color printing, comprising a plurality of reversible register control motors for registering said imprints relative to one another, a plurality of control units each having two thyratron tubes connected to one of said respective motors for energizing it to run in one or the other direction depending upon which of said tubes is conductive at a time, grid circuits associated with said respective tubes, circuits for controlling the latter, biasing means in each grid circuit ior imposing thereon a direct-current bias voltage, an alterhating-current circuit connected with each grid circuit for imposing thereon an alternating grid voltage and comprising controllable phase-shift means for rendering said tubes conductive and nonconductive; a plurality of impulse-transmitting photo-electric scanners for issuing control impulses in response to the passage of printed register marks, a plurality of electronic mixer units each being input-connected to two of said scanners to be jointly controlled by the impulses from said two scanners and being output-connected to phase-shift means appertaining to said two tubes of one of said control units respectively for causing said phase-shift means to render one or the other of said tubes conductive depending upon whether the impulses from one of said two scanners lead or lag those from said other scanner.

8. A register regulator for registering imprints in multi-color printing, comprising a plurality of reversible register control motors for registering said imprints relative to one another, a plurality of control units each having two thyratron tubes connected to one of said respective motors for energizing it to run in one or the tubes is conductive at a time, grid circuits associated with said respective tubes, circuits for controlling the latter, biasing means in each grid circuit for imposing thereon a direct-current bias voltage, an alternating-current circuit connected with\each grid circuit for imposing thereon'.

an alternating grid voltage and comprising controllable phase-shift means for rendering said tubesconductive and nonconductive; energizing means disposed for connection to an alternatingcurrent line and connected with said' tubes to providel plate-energization therefor and also connected with said biasing means so as to vary said bias voltage in response to uctuations in line voltage in order to compensate the effect of such fluctuations on the control of said tubes; a plurality of impulse-transmitting photo-electric scanners for issuing control impulses in response to the passage of printed register marks, a plurality of electronic mixer units each being inputconnected to two of said scanners to be jointly controlled by the impulses from said two scanners and being output-connected to said phase shift means appertaining to said two tubes of one of said control units respectively for causing said phase-shift means to render one or the other of said tubes conductive depending upon whether the impulses from one of said two scanners lead or lag those from said other scanner.

9. A register regulator for registering imprints in multi-color printing, comprising a plurality of reversible register control motors for registering said imprints relative to one another, a plurality of control units each having two rectifier circuits each containing two thyratron tubes interconnected for full-wave rectification, said rectier circuits being connected to one of said respective motors'for energizing it to run in one or the other direction depending upon which of said rectifier circuits is conductive at a time, each of said rectier circuits having grid circuits associated with the appertalning two tubes for controlling the latter; said two tubes of each rectifier circuit having plate circuits provided with common alternating-current energizing means for attachment to an alternating-current line, biasing means disposed in said respective grid circuits for imposing a `direct-current bias thereon, alternating-current circuits connected with said respective grid circuits for imposing thereonv an alternating grid voltage and comprising controllable phase-shift means for rendering said tubes conductive and non-conductive, said plate circuits of each rectier circuit having a common direct-current branch connected to said biasing means of the appertaining grid circuits so as to vary said direct-current biasin response to fluctuations in line voltage in order to compensate the effect of such fluctuations v relative to the control of said tubes, a plurality of impulse-transmitting photo-electric scanners for issuing control impulses in response to the passage of printed register marks, a plurality of electronic mixer units each being input-connected to two of said scanners to be jointly controlled by the impulses from said two scanners and being output-connected to said phase-shift means appertaining to said two tubes of one of said control units respectively for causing said phase-shift means to render one or the other of said tubes conductive depending upon whether the impulses from one of said two scanners lead or lag those from said other scanner.

Y current grid bias therefor and being 10. A register regulator for registering imprints in multi-color printing, comprising a plurality of reversible register control motors for registering said imprints relative to one another, a plurality of control umts each having two thyratron tubes connected to one of said respective motors for energizing it to run in one or the other direction depending upon which of said tubes is conductive at a time, grid circuits associated'with said respective tubes, circuits for controlling the latter, biasing means in each grid circuit for imposing thereon a direct-current bias voltage, an alternating-current circuit connected with each grid circuit for imposing thereon an alternating grid voltage and comprising controllable phase-shift means for rendering said tubes conductive and non-conductive; energizing means disposed for connection to an alternatingcurrent line and provide plate-energization therefor and also conbiasingr means a plurality of impulse-transmitting photo-electric scanners for issuing control impulses in response to the passage of printed register marks, a plurality of electronic mixer units each having two detector tubes associated with two switching tubes, said detector tubes being grid-connected to two of said scanners to be controlled by the impulses from said latter scanners respectively and being plate-connected to said respective switching tubes to control the latter for conductance and non-conductance, means connected to said detector tubes to provide directattachment to render one or the other,of said thyratron tubes conductive depending upon whether the impulses irom one oi said two scanners lead or lag those from said other scanner.

,11. In combination with a multi-color printing press having a plurality oi' successive printing stands for producing respective diierently colored imprints on a web and having means for passing the web successively through said stands, a register control system comprising a photo-electric master scanner located at the iirst stand for issuing recurrent connected with said tubes to xfor causing said tubes prints respectively for issuing one of said series of impulses in a fixed phase relation to the printing of the first imprint, a plurality of photo-electric color scanners located near the printing places of the respective subsequently printed impressions for issuing respective .other series of impulses in response to the passage of the register marks, a first cable connection disposed between Said maste:` scanner and one of said grid circuits of each of said mixer units, a group of cable connections disposed between said respective color scanners and saidvother grid circuits o1' said respective mixer units, step-down impedance matching means interposed between each of said scanners and the appertaining cable connection, and step-up impedance matching means interposed between each of said cable connections and the respective grid circuits.

13. A register regulator as set forth in claim 12, in which said impedance matching means of said scanners comprise an electronic vacuum tube and an impedance connected in series-relation to each other across the cable connection attached to the scanner, said tube being connected to the appertaining scanner so as to have a stage gain of less than unity.

LLOYD C. POOLE.

REFERENCES CITED UNITED STATES PATENTS 'Number Name Date 2,230,715 Cockrell Feb. 4, 1941 p 2,396,706 Kott Mar. 19, 1946 FOREIGN PATENTS Number Country Date 530,314 Great Britain Dec. 10, 1940 

